The present invention relates to communications systems that provide service to communications units over a plurality of coverage areas and more specifically to providing contact information for such a unit identified by a uniform resource name (URN).
Communications systems that provide service to communications units over a plurality of coverage areas are known. Such systems include various Wide Area Networks such as present and planned cellular or wireless phone and data systems. Current versions of such systems include cellular phones or communications devices that have a phone number and normally have an associated home coverage area or area that the device or unit normally operates within known as the home area. Particulars regarding the device, billing information, and services available are found within the memory or database known as a home location register (HLR). When the device roams out of the home area and into another area it will register with that visited system. The visited system will contact the home system or HLR and obtain the appropriate information which is then retained in a local visiting location register (VLR).
When the unit comes within the home coverage area and is activated or powered on, it registers with the system and the unit phone number or other information is recognized and services provided according to the information within the home location register. When the unit is activated in the visited coverage area and registers with that system it normally will be recognized as a visitor to the system. The device particulars such as phone number are sufficient for the visited system to contact the proper HLR to obtain the billing information and services information which will be stored within the VLR associated with or local to the visited system. The HLR when contacted will be updated to include information that points to the VLR. When the unit originates a call the appropriate information will be available to provide correct services and collect and forward to the HLR proper billing information.
A second unit wishing to contact the unit will contact the HLR, if registered with the same home area, and be forwarded to the VLR. If registered with a different home area, the second unit will contact its local VLR and if no information related to the unit is found, it will be directed to the HLR and thus to the VLR. Thus second units registered with the visited system will be able to contact the unit directly while all others will have to go through the HLR suffering the inherent latency that entails. When the unit roams out of the visited system and registers with another system a new VLR will contact the HLR and the HLR will forward information resulting in the other VLR de-registering the unit and the HLR being updated to point to the new VLR. In essence there can only be one HLR and one VLR and any communications units that are not within the same coverage area as the unit they wish to contact will suffer some additional latency in call setup while the proper contact information is being collected or determined or located.
Communications systems such as GPRS or those being planned use or may use internet protocol addressing such as IP version 6 or IPv6 where units will have a unique uniform resource indicator (URI) or more specifically a uniform resource name (URN), for example, of the form urn:wireless:800-555-1234. A URN is a subset of URIs normally used to provide a unique name having persistence as an identifier for an entity. The URN as the name suggests provides a unique designator for a unit or entity and should not be confused with a uniform resource locator (URL) that may take various forms. For example, a URL corresponding to the above URN may be of the form sip:+1-800-555-1234@wg.wireless-network.com, or if the URN corresponds to a URL for an IP address, the URL may be of the form sip:adam@10.1.2.3. A URL identifies a network location and a URL is again a subset of URIs. When a computer or unit or the like moves it will have a new URL but can retain the same URN. In these systems a problem of associating URNs and URLs will be with us much as the problem of associating phone numbers and locations is now with us.
What is needed is a method and apparatus for efficiently and effectively obtaining contact information and minimizing any session setup delays resulting therefrom.